Evaluation of Matricaria aurea Extracts as Effective Anti-Corrosive Agent for Mild Steel in 1.0 M HCl and Isolation of Their Active Ingredients

Abstract

Plant extracts have shown promising corrosion inhibitive actions for different metals in diverse corrosive climate. In numerous studies, it has been demonstrated that corrosion inhibitive features of plant extracts are due to the presence of complex mixtures of phytomolecules in their composition. However, rare efforts have been made to identify those phytomolecules accountable for the activity of the extracts. Therefore, in this paper, several Matricaria aurea extracts were prepared and assessed for their anticorrosive actions for mild steel (MS) in corrosive media (1.0 M HCl). Among the tested extracts, the methanolic extract showing the utmost anticorrosive activity was selected and processed further to identify its active phytomolecules, which led to the identification of a novel green corrosion inhibitor, MAB (Apigetrin). Furthermore, the anticorrosive properties of MAB on MS were evaluated comprehensively involving gravimetric, linear polarization, Tafel plots, EIS, and techniques like SEM and EDS. These findings expose that MAB performs like a mixed-type inhibitor and conforms the isotherm of Langmuir adsorption model. Moreover, the MS surface via SEM techniques exhibits a remarkable advanced surface of the MS plate in the company of MAB. The outcome of results through electrochemical analysis and weight loss methods were in good consonance, which depicts remarkable inhibition properties of the novel green inhibitor MAB.